Birthday Calendar Guestbook

I really love the idea of guests being able to write greetings and well-wishes to us at our wedding. Its kind of like having your friends sign your yearbook and pouring over all of the notes at the end of the school year.

I was inspired today by Foy and Jeff's (of A Low Impact Wedding) fantastic calendar guestbook. Their guests left comments and wishes for them in a calendar on their birthday or anniversary. Because what are you going to do with a guestbook after the wedding anyway? In their words, "Put it in a box where it can clutter up the place." But the same problem ensues with a normal calendar for that year once the year is over.

Another problem is that the squares for each date greatly limit how much the guests can write. I want people to be encouraged to fill up a whole page if they want to, or draw a sketch, write a poem or whatever they want. Enter the perpetual birthday calendar. My idea is to use a 200 page spiral bound sketchbook, and use both sides of each page label each one page for each day of the year. You could use rubber stamps to decorate and do the lettering. Then guests would have a lot of space to write, and you could use the calendar perpetually, flipping the page each day.
These are kind of boring but I'm sure there are other sets out there. I haven't put this idea into practice yet, but am definitely considering it!